Cushioning mechanism



Oct. 1,- 1940. M. P. BLoMBl-:RG 2,216,429.

cusHIoNI'NG MEGVH'ANISM v Filod lay 20, 1937 3 Sheets-Sheet 1 INVENTOR ATTORN Y 1,1940. M. |=.l BLoMBl-:RG

" cUsHIoNING 'MEGHANISM 4 rind 'nay 2o, 1957 5 Sheets-Sheep 3 34 as a Fig. 11i

INVENTOR Martin l? Blomberg ATTORN Patentedv Oct. 1, 1940 UNITED gSTATES PATENT OFFICE cUsmoNmGMs 1 Martin P. Blomberg, Hinsdale, El., assignor to National Malleable and Steel Castings Com-` pany, Cleveland, Ohio, a corporation of Ohio Application May 20, 1937, ScrialNo. 143,695

15 Claims.

.cushions positioned between elements thereof.'

The invention is shown as embodied in a railway draft gear wherein various advantages thereof are especially well illustrated.

On certainv types of cars and locomotives the space available for 'the draft gear pocket is very limited. A draft gear made in accordance with my invention is particularly adaptable for use in such a limited space and when so used may be constructed so as to give sumcient l5 capacity and travel required for the operation of the vehicle. An object of my invention is to provide a draft gear which while shcrter than the usual friction type of gear has an action over the rst portion of its travel similar to that of a free spring, but which at the end of its travel builds up resistance rapidly, somewhat analagous to the latter part of the travel of the usuall friction type gear. Experience has shown that this action-is -very desirable, especially on 23\passenger cars and locomotives, in absorbing the small shocks and pulsations incident to normal .operation Iof the train and the operation of coupling up the cars, and at the same time a large reserve of capacity is available for heavy shocks..

My invention, in brief, has been illustrated in connection with a railway draft gear and comprises as one of its features a plurality of rubber elements mounted between the two wedge 25 followers of the draft gear in such a vmanner as to be placed under combined compression and shear during movement of either of said members towards the other. The invention also comprises a connection between the draft gear and Y yoke whereby the latter may tilt in a. vertical Figure 1 is a section through a portion of a as car body to which the -draft gear has been ap'- (Ci. Z13-4(9) plied, showing a typical application of the gear to the yoke and associated attachments.

Figure 2 is a view ofmy draft gear partly in plan and partly in horizontal section, taken on line 2--2 of Fig. 3. l

Figure 3 is a view partly in elevation and partly in vertical section, taken on line H of .Fig. 2.

Figure 4 is a partial sectional view taken on line 6--4 of Fig. 3.

Figure 5 is a diagram showing typical curves representing pressure travel characteristics of rubber under compression alone and shear alone.

Figure 6 is a diagram showing a typical pressure travel curve of a. 'draft gear embodying my 15 invention.

Figure 7 is a view partly in elevation and partly in vertical section, showing my invention applied in two units to the draft attachments.

Figure 8 is a view partly in elevation and partly 20 in vertical section, showing a'modied form of the invention in which a rubber unit is placed at each end of the draft gear.

Figure 9 is a view partly in elevation and partly in vertical section, showing a' further modifica,- 25- tion of the invention.

Figure 10 is a transverse sectional view taken on1ineIil-iiIofFig.9;and

Figure l1 is a view showing a modified arrangement of the rubber elements. 80

l In Fig. 1 of the drawings, lli is a part of the car structure to which is secured a cast or fabricated member Il which forms the draft gear pocket. Stop lugs l2 are provided on each side of the pocket at the rear end thereof and similar 35 lugs I3 are formed at the forward end of the pocket. The draft gear` i4 engages a surface I 5 on each of the rear stop lugs and a surface I6 on the forward lugs. A. yoke i1- is preferably formed with an upper horizontal arni I8 and a 40 lower arm I9 that are-positioned above and below the draft gear. A rear wall 20 joins the arms rearwardly of the draft gear and wall 2i connects-the arms at the forward end thereof. Rear wall 20 has an inner draft gear engaging 45 surface 22 and wall 2| 'has a similar surface 22, both of said surfaces being curved about a center point substantially midway between the two surfaces. By forming these surfaces in this manner the yoke may tilt upwardly or down- 5i) wardly without disturbing the relation between the engaging surfaces of the draft gear and stop lugs.

The yoke forwardly of wall 2| may be shaped in any desired. manner for connection to the shank of the associated car coupler. I have shown the usual swivel type of `connection between the yokeand shank 24 in which the yoke is formed with spaced arms 25 and the shank with rearwardly extending arms 26 projecting into the spaces between arms 25. A vertical pin passing through suitable openings in arms 25 and 26 pivotally connects the coupler shank with the yoke.

The forward end of the draft gearpocket may be constructed to receive a resiliently mounted carrier iron which supports the shank of the coupler and at the same time permits vertical angling of the coupler shank and yoke with-respect to the car. The pocket 21 receives spring 28 that extends between bottom wall 29 ofthe pocket and the carrier iron 30. The spring 28 maintains the shank in horizontal position when the car is not coupled with another car. However, when the two cars are joined, shank 24 can move downwardly against the resistance of spring 28. Furthermore, clearance is provided, as at 3 l -to permit shank to tilt upwardly.

Referring particularly to Figs. 2, 3 and 4, the draft gear I4 comprises a` wedge member 35 formed with a base portion 36 andrarms 31, the latter having inner surfaces 38 diverging in a direction away from said base portion. A V- shaped block 39 is provided with wedge surfacesl 40 converging toward the member 35, the angle between the surfaces 4,0 being substantiallythe same as the angle between surfaces 38. As shown in the drawings, a portion of block 39 extends into the opening between arms 31 of the wedge member. Arms 31 are joined by tie members 4l which serve to reinforce the wedge and limit lateral movement of block 39 relative to the wedge. 1 Y

Between surfaces 38 and 40 are positioned cushioning units 42, each comprising a plate 43 and 44 with a block of resilient material such as rubber bonded or vulcanized tothe plates of each unit.4 It will be appreciated that upon inward movement of wedge block 39 forces will be applied to member 35, through rubber units 42, tending to spread arms 31 apart. However, tie members 4|', which join the arms together in the zone of maximum bursting stress, adequately overcome this spreading tendency.

wedge member 35 is formed with stops Su' adapted to be engaged by the inner end of each plate 43 to limit inward movement thereof. Likewise, block 39 is formed at its outer end with extensions 5| that overlie the outerends of plates 44 so that as block 39 moves toward the wedge, plates 44 will be carried along with it. It will be understood that relative movement of wedge 35 and block 39 towards each other will reduce the distance between plates 43 and 44, resulting in compression of rubber blocks 42. Furthermore, since .during such relative movementA plates 43 move with wedge 35 and plates, 44 move vwith block 39, the portions of the rubber blocks adjacent plates 43 and 44 will be moving in relatively opposite directions, causing the rubber to be subjected to shearing stresses. -It is thusapparent that during compression of my draft gear the rubber is under a combined compression and shearing stress.

In order to umu. the trave1 of the draft gear and prevent the rubber from being over stressed,

" extensions 52 are formed. on block 39 which engage outer surfaces 53 of tie members 4I to take the over-solid blows. It will be observed that there is clearance between the lateral edges 54 of the rubber units and the inner surfaces of the tie members 4I so as to permit the rubber to' flow as itis being compressed. In other words, as

plates 43 and 44 move closer together the outer surfaces 54 of the rubber blocks bulge outwardly. It is undesirable to permit thev rubber units to shift laterally with respect to wedge member 35 as surfaces 54 of the rubber blocks might at times rub against the-tie members. I therefore recess arms 31 of the wedge member, as shown more clearly in Fig. 4, so that stops 55 are provided,

adjacent plates 43 to limit lateral movement thereof and prevent contact between the rubber and tie members.

The base portion 36 of the Wedge member has )surfaces 56- for engagement with surfaces I5 on the rear stops l2 in the draft gear pocket. Likewise member 39 has surfaces 51 adapted 'to en` 'tically without disturbing the engagement of the draft gear with the stop lugs. While I have shown the gear applied with member 39 toward the coupler, it will be understood that my gear can be reversed if desired, as both ends are of the same curvature. In addition, the use of resilient material between't'he two members of the draft gear permits a limited amount of twisting movement be- `tween wedge 35 and block 39. For example, if

we assume a draft stress in the coupler shank the yoke will transmit the stress to the draft gear,

` causing the latter to be compressed and surfaces .56 to move away from the rear stop lugs. At the same time surface,23 of the yoke will move away from surface 59 on block 39. When in this position, any twisting of the coupler shank about its longitudinal axis will rotate the yoke and member 35 with respect to block 39. This twisting will, of course, be resisted' by the rubber blocks. In this manner the coupler shank and yoke are relieved of dangerous twisting strains. My novel draft gear construction has a further advantage in that blows to the coupler whenthe latteris angled relative tothe car may be readily transmitted to and absorbed by the draft gear without putting any severe strains on the gear since wedge block 39 is free to angle a limited extent in any dgection relative to wedge 35. In this connection it may be noted, as shown in Figs. 2 and 4, the members 4I of the wedge 35,are spaced from the side walls of the block 39.

The wedge block and the v-blo'ek may be nghtened by forming openings vlil) in the former and 6| and 62 in the latter without materially reducing their strength. It will thus be apparent that my invention provides a draft gear simple and compact in construction which permits it to lbe placed in a draft gear pocket smaller than normal and which is formed so as to cooperate with va yoke in s'uch a manner that the latter can readto the sine of 321/2 degrees or .537";

vbetween the lates 43 and v4l! will be .843".

asians and a reserve of resistance, near the end of its travel, for heavier shocks. Moreover, my improved draft gear is susceptible of modication to vary the characteristics of travel and capacity simply by changing the angle between the wedging surfaces on blocks 35 and 39. As the angle between these surfaces is' increased, the rubber will be subjected to a greater compression stress and less of'a shearing stress. Conversely, as the angle is decreased the shearing stress will be greater and the compression of the rubber less. Since the load required to deflect 'the rubber a given amount is greater in compressionthan in shear it follows that by varying the wedging angle the characteristics of my gear may be varied over a wide range.

In Figs. 5 and 6 there are illustrated typical curves showing the pressure travel characteristics of rubber. In these figures the horizontal axis represents the compression or travel, as the case may be, and the vertical axis represents the pressure. Curve A represents a typical curve of rubber placed only4 under compression. When the rubber is subjected only to shearing stresses the pressure travel characteristics are similar tocurveB. Curve C is an actual curve resulting from a test on a draft gear embodying my invention. In curve C the rubber was subjected to both compression and shear. In each curve the upper'line represents the compression stroke land the lower lines the release of the rubber.

The area between the two lines, in each case, is a measure of the energy absorbed by the rubber. By so arranging the rubber units that they are subjected to the combined stresses, the greater resistance offeredjbythe rubber under compression for a given amount of travel is utilized in connection with the increased travel of rubber subjected to shear. Thus when absorbing the severe shocks encountered in railway service the draft gear hasa greater travel, and hence a greater time interval, in which to absorb the blow. A draft'gear in which the rubber is placed only in shear would not offer sufficient resistance to protect the vehicle, whereas if onlythe compressive action of the rubber were utilized a much larger quantity would be required to provide the same amount of travel.

By placing the rubber units of my draft gear at an acute angle to each other, they are sub jected to combined compressionv andv shear stresses, the resulting capacity of Whichfor a given amount of travel depends upon the angle between the rubber units. It will be apparent that the amount'the rubber in each unit is cpmpressed for a given travel of the draft gear will be equal to the travel times the sine of onehalf the angle between the rubber units. For example, in the draft gear illustrated in the drawings the rubber units are placed at an angle of 65 degrees to each other. If we consider that themembers35 and 39 have moved towards each other one inch, then the lrubber of each unit will be compressed an amount equal Likewise, the amount of movement in shear represented by relative movement between plates 43 and 44' will be equal to the trave1 of the draft gear times inch the relative movement `in a shear direction For railway draft gears I prefer that the amount of deflection of -the rubber blocks in compression should be equal to at least of-the relative movement between the members of the draft A' the less capacity for a given wedge angle andr viceversa. It is apparent therefore that my invention provides a very compact ldraft gear that can be adapted to widely varying service conditions by the proper selection `of rubber fcomposition' and wedge angle.

To facilitate shipping and insertion of the draft gear in the yoke it is desirable that the parts of the gear 'be held together temporarily and insuch a manner that they can be readily released fo-r operation after being placed in the yoke. I have shown V-block 39 provided with a groove 63 receiving a Wire 64 that passes through the openings between members 4| and tbase portion 36.150 limit outward movement of said block relative to member 35. Members 35 and 4I are preferably held in a slightly compressed position so that the draft gear as a whole may be'slid into the yoke .after Whichfwire 64 may be cut and drawn outof groove 63. The groove is preferably deeper than the diameter of the wire to facilitate withdrawal of the latter.

In Fig. '7 there is shown a draft rigging in which the cushioning unit embodying my invention is placed within the yoke and anothersuch unit is positioned to the rear of the yoke. The cushioning unit 10 is substantially the same as the one shown in Figs.y 1 and 3, except that block H has a surface 'l2 curvedin the opposite direction from surface 59 of the previously described form of the invention. Yoke 13 has an enlarged portion 14 at its rear end provided with curved surface 15 which cooperates with surface 12 on brook 1|. Rubber unit 16 to the rear of the yoke is similar to unit vI0 and is formed with a curved surface 11 at its forward end whichl cooperates with curved surface 18 at the rear of portion 14. By reason of the above described curved surfaces theyoke may tilt a limited amount in avvertical plane without disturbing the :positions of the cushioning mechanisms. The units 10 and '16 are arranged'so that only unit 10 operates in draft and only unit 16 operates in buff. With such a construction the two units may be made so as to have different characteristics. so as to meet^ widely varying conditions of draft and buff. If desired, stops may be provided to prevent rearward movement of block '|I, in which case both-units would operate in buff. A stop`19 is fastened tothe sills on each side of unit 16 so as to prevent forward movement/.thereof when the yoke moves forward under draft. Plates and 8| secured to the sills support the cushioning mechanism in the draft gear pocket.

In the modification shown in Fig. 8, member 82 is providedat each end with Wedging surfaces 83 which receive rubber units 84 lsimilar to those shown in Figs. 1 and 3. engage the'rubber units and cause them to be placed'under combined compression and shear stresses and may be formed with fiat surfaces 86 engaging the ends of the yoke. In such case any vertical tilting oflthe .yoke relative to the draft gear would be resisted by the cushioning action of the rubber units. If desired, surfaces 86 and the cooperating surfaces on the yoke could be curved similar to` the 4corresponding surfaces of the embodiment shown in Fig. 1.

5 In this modification both of the rubber units would be active in both buff and draft.

In Figs. 9 and 10 the base casting 81 is cylindrical and is formed with a conical recess for receiving the rubber unit. Plates 88 and 89 are 10 also conical in shape, as is the rubber block 80.

Member 9| is likewise formed with conical surface 92 which fits into plate 89. In this form of the invention the force applied to the draft gear would cause the rubber to be placed under combined compression and shear around the entire circumferenceof the gear. As a variation of this embodiment the recess in boss 81 could be made rectangular in cross-section and member 9| correspondingly shaped in the form of a pyramid.

Fig. 11 shows a little different form of rubber unit in which two blocks 93 are secured to plate 94 and are separated,-as at 95, so as to allow for an additional flow of rubber. It is, of course, un-

derstood that, if desired, more than two blocks could be used to further change the characteristics of the gear. Moreover, it will be apparent that, in any of the other embodiments shown, the rubber means may be broken up intovgseveral 80 blocks instead of using a single piece.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the u se of such terms and expressions, of excludingany Il equivalents ,of the features shown and described or portions thereof, but recognize that. various modifications are possible withinthe scope of the invention claimed.

What I claim is:

1. In a cushioning mechanism for railway vehicles, a base member having a pair of forwardly extending diverging arms each having substantially' flat inner surfaces, a wedge member posi- -tioned between said arms, and having outerv converging substantially flat surfaces spaced from and substantially parallel to said inner surfaces on said arms,A and rectangular shaped rubber means extendingbetween -said surfaces on said members adapted to resist movement of said members towards each other, all thelateral edges of said rubber means being free :to expand under compression of the rubber.

2. In a cushioning mechanism for railway vehicles, a base member having a pair of forwardly extending diverging arms, a wedge member positioned between said arms, and having outer converging surfaces spaced from and substantially parallel to inner surfaces on said arms, and rectangularly shaped rubber means extending between said surfaces on said members, said members and said rubber means being so constructed and arranged as to place said rubber under combined compression and shear during movements of said members towards each other, all the lateral edges of said rubber means being-free to expand under compression of the rubber, the angle between vsaid surfaces on said base and we dge members being suchthat the compressive deection in said rubber means is equal to at least 40% of the movement of said members towards each other. #s

3s, A cushioning mechanism for railway vehicles comprising a pair of spaced, relatively movable members each formed with a pair of angularly A75 arranged plane surfaces, stop lugs onsaid members, and separable rectangular rubber units extending between said members and engaging said stop lugs for resisting relative movement of said members towards each other, all the lateral edges of said rubber units being free to expand under compression of the rubber.

4. A cushioning mechanism for railway vehicles comprising a pair of spaced, relatively movable members each formed with a plurality of angularly arranged surfaces, stop lugs on said members, cushioning umts positioned between said members and engaging said surfaces, each of said units comprising a rectangular rubber block and a pair of elements bonded to opposite sides thereof, the remaining sides of each of said blocks being spaced from said members to provide for flow vcompressive and shear stresses to be nset up in said rubber blocks, theangularity of Said faces being such `that the compressive deflection in said 'blocks is equal to at least 40% of the relative movement between said members.

6. A draft gear comprising an outer j aw-shaped member and an inner wedge-shaped member arranged to move toward one another, the opposing faces of said members being positioned at an angle to the direction of relative motion, rubber means engaged on opposite sides by said angularly arranged faces to resist relative movement of said members, all the lateral edges of said rubber means being free to expand under compression of the rubber, said means being adapted to transmit stresses from said wedge member to said jaw member capable of bursting the latter, reinforcing means spaced from said rubber` means and joining the jaws of said outer member and capable of successfully resisting said bursting stresses,

and means on said wedge shape member adapted to engage said reinforcing means to limit relative movement of said members in one direction.

- 7. A draft gear comprising an outer jawshaped member and an inner wedge-shaped member arranged to move toward one another, the opposing faces of said members being positioned at an angle to the direction of relative motion, said inner member having substantially parallel side walls joining said angled surfaces on said member, rubber means engaged on opposite sides by said angularly arranged surfaces to resist relative movement of said members, all the lateral edges of said rubber means being free to expand under compression of the rubber, and-a y pair of members joining the jaws of said outer member and spaced from said side walls to enable relative rotational movement between said inner and outer members about the longitudinal axis thereof. a

8. A cushioning mechanismfor railway vehicles comprising a pair of relatively movable members arranged to alternately move toward oneV another, the opposing faces of said members being positioned at an angle to the direction of relative motion, rubber means interposed between said angularly arranged surfaces to resist relative movement of said members, the sides of said rubber means being spaced from adjacent portions of said members to permit liiow of the rubber, and means on one of said members limiting lateral movement of said rubber means so as to prevent contact thereof with adjacent portions of said members during flow` of said rubber.

9. In a railway draft rigging, a draft gear and a yoke, said draft gear comprising a pair of relatively movable members each having a surface adapted to engage said yoke, resilient means between said members opposing movement thereof towards one another, a groove in one of said members extending across the surfaceof said member and adjacent the engaging surface on said yoke, and means in said groove and' passing through the other of said members Afor holding the draft gear in assembled relation.

10. In a railway draft rigging, a draft gear and a yoke, said draft gear comprising a pair of relatively movable members each having a'surface adapted to engage said yoke, resilient means between said members opposing movement thereof towards one another, a groove in one of said members extending across the surface of said member and adjacent the engagingsurface on said yoke, and a wire in said groove and passing through the other of said members for holding the draft gear in assembled relation.

11. In a railway draft rigging, a draft gear and a yoke, said draft gear comprising a pair of relatively movable members each having a surface adapted to engage said yoke, resilient means between said members opposing movement thereof towards one another, a groove in one of said members extending across the surface of said member and adjacent the engaging surface on said yoke, and a Wire in said groove and passing through the other of said members for holding the draft gear in assembled relation, the diameter of said wire being less than the depth of said groove so as to facilitate removal of the wire after the draft gearhas been inserted in the yoke.

12. A cushioning mechanism comprising a pair of spaced,l relatively movable wedge members each formed with a pair of angularly arranged surfaces, a member intermediate said wedge members formed at opposite ends thereofwith angularly arranged surfaces complementary to said wedge surfaces, and rubber means between said surfaces adapted to be placed in combined compression and shear to resist alternate movement of said wedge members toward said intermediate member. y

13. A draft gear for railway vehicles comprising spaced interiitting members, draft means lfor producing relative movement between said members, and means for absorbing light draft loads 15. A cushioning mechanism comprising a pair of relatively movable members, one of said members having a recess formed with diverging surfaces and the other of said members projecting into said recess and having outer converging surfaces, rubber means extending between said surwith a low resistance and heavy shocks with substantially greater resistance, said means comprisfaces adapted to be placed under combined compression and shearing stresses to resist movement ofsaidmembers towards each other. all the lateral edges of said rubber means being free to-expand under compression of the rubber, the anguarity of said surfaces beingl such that the compressive deflection in said blocks is equal to at least 40% of the relative movement between said members andstbp-lugs on said members for limiting movement 'f said rubber means in a plurality of directions.

` I!AIIIIIII'` P. BLOMBERG. 

